Inertial measurement units (“IMU”) are used to track changes in velocity and acceleration of moving objects without the use of a pre-calibrated external reference. Typically, an IMU includes electronics devices, such as gyroscopes and accelerometers. The electronics devices sense real-time rotational and acceleration data that are compared to reference data stored in the IMU. The compared data is then used to calculate a current position of the moving object.
Because IMUs operate virtually independently from other devices after receiving the reference data, they have been considered for implementation onto towed artillery systems. Specifically, IMUs have been investigated as devices for improving targeting accuracy of guided projectiles fired from the artillery systems. However, several obstacles have been encountered. For example, one or more IMUs are typically included as part of an inertial sensor assembly (“ISA”) that is mounted in a chassis along with additional electronics. The ISA, and hence, the IMU, comprise part of an inertial navigation system (INS), which may be coupled directly to a platform on the towed artillery system. When one or more rounds of projectiles are fired from a barrel of the system, the INS, and hence, the IMU, experience a very high shock (e.g., greater than 40 G). The very high shock may cause the electronics devices within the INS to decouple from the chassis and to have a significantly decreased useful life.
To improve the useful life of the electronics devices, elastomeric isolators have been included between the chassis and the platform. Although displacement of the ISA relative to the platform is decreased by the elastomeric dampers, the ISA may still experience an undesirable magnitude of acceleration in response to the very high shock. In particular, the ISA and the platform may resonate in phase to thereby amplify an acceleration input into the system. Additionally, in instances in which the barrel may undergo rapid firing sequences, positioning of the INS, and hence, the IMU, relative to the system platform may change between shots, and the elastomeric isolators may not be capable of minimizing the positional changes (i.e., improved repeatability). As a result, the positional changes may affect the operability and pointing accuracy of the INS.
Accordingly, it is desirable to have a damping system that improves a useful life of an IMU that can be used in conjunction with a towed artillery system gun. In addition, it is desirable to have a damping system that provides repeatability of the INS and hence, the IMU, relative to the gun. Furthermore, other desirable features and characteristics of the inventive subject matter will become apparent from the subsequent detailed description of the inventive subject matter and the appended claims, taken in conjunction with the accompanying drawings and this background of the inventive subject matter.